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CVE-2026-126265

7.4, high

SiYuan 2.1.0 before 3.8.9 contains a flaw where the loginAuth CAPTCHA challenge lives in a signed client-side cookie, allowing reuse of…

NVD (opens in a new tab) CVE.org (opens in a new tab)
CVSS
7.4, high high CVSS v3.1
EPSS, next 30 days
0.4% higher than 29.8% of scored CVEs
Exploitation
No public evidence
Published
13 Nov 2026yesterday

Description

SiYuan 2.1.0 before 3.8.9 contains a flaw where the loginAuth CAPTCHA challenge lives in a signed client-side cookie, allowing reuse of a solved challenge. Attackers can replay the original signed siyuan cookie with distinct wrong access codes to brute-force the code and gain an administrator session.

Details

Vendor
Siyuan-note
Product
siyuan
Weakness
CWE-307 (opens in a new tab)
Status
Deferred
Updated
13 Nov 2026
Assigner
disclosure@vulncheck.com

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

References 2

Advisories 1

Other references 1

The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.

Other Siyuan-note CVEs

Every Siyuan-note CVE we hold

Same vendor in what we hold, not a known link between the flaws.

  • CVE-2026-126264 Siyuan-note siyuan Exposure of Sensitive Information Vulnerability EPSS 0.5% 7.7, high
  • CVE-2026-85175 SiYuan versions <= 3.8.1 (fixed in v3.8.2) contain an incomplete blocklist in the IsForbiddenAbsPath() function… EPSS 0.3% 8.8, high

Beyond this page

Is CVE-2026-126265 in your network?

This page tells you how dangerous CVE-2026-126265 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.

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Check your exposure

Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 14 Nov 2026, not the live upstream state.